Why do some families see more than their fair portion of twinned births?Identical twinsare a random surprisal , but scientist know that non - identical ( or biovular ) twins have a genetic link . Finding the specific factor involve , however , has been another story . Now , unexampled inquiry has break up up on seven cistron , and a psychometric test for them could not only help learn your chances of ingest similitude , but also reveal clues about yourfertility .

“ It has long been have it off that brotherlike twins have a genetic base , with non - identical twins often running in folk , ” said Professor Nick Martin , lead study author and a professor at QIMR Berghofer Medical Research Institute , in astatement . “ However , identifying the transmissible factors which cause fraternal Twin has been like look for a needle in a haystack . ”

But procession in technology have made all the departure . Arriving at the turn of the millennium , gene buffalo chip – or DNA microarrays , as they are also known – made it possible to supervise the expression of thousands of gene simultaneously .

“ We combined data from five independent subject area in Australia , The Netherlands , United States , United Kingdom ( UK ) and Iceland on 8,265 mothers of spontaneous DZ [ dizygous , another word for non - very ] twins and 264,567 controls , as well as UK , Finnish and Swedish data on independent DZ matching materialisation , ” Professor Martin explain , which led to the designation of nearly a million factor variants across all 23human chromosome .

The squad of scientists then compare the absolute frequency of these variants between mother of fraternaltwins , biovular Gemini themselves , and mothers of individual materialisation in a character of analysis predict a genome - wide association study , or GWAS .

In the terminal , seven gene stand out . Five of them are already know to have role in the follicle energize internal secretion ( FSH ) pathway , which is a key part of the distaff reproductive system , but two had never antecedently been associated with the possibility oftwinbirths .

“ This is just the beginning , ” said Professor Martin . “ We have isolated seven gene but we know there are more to bump . As the routine of mother in our study increases , we will be able-bodied to identify more genes and to predict which cleaning lady may be super - fecund and prone to make Twin . ”

On the snotty-nosed side , genic examination free-base on these findings could also have the potentiality to key women who may havedifficulty conceiving . This face of the research was particularly important to study participant Saskia Bollmann , who was the first in her sept to have Twin Falls when two - twelvemonth - erstwhile Max and Pip hail along .

“ I realise the aptness to have twins is also related to fertility , and we have seen many friends struggle with fertility , so from that perspective this research is very important , ” Bollmann articulate .

And if you are the female parent ofnon - identical twin , you could get take too . Professor Martin and the team are still actively recruiting participant for the ongoingGenetics of Dizygotic Twinning cogitation . You ’ll want to respond a short questionnaire and provide a saliva sampling .

For Bollmann , it was a no - brainer . “ I signed up for the field . It was gentle and elementary . For gene studies to be meaningful they need many participants and I believe it ’s really valuable . I would unquestionably encourage other mothers of twins to enter in the study . ”

The study is published in the journalHuman Reproduction .